This invention relates to a pressure swing adsorption apparatus for generating product gas, and in particular, relates to an arrangement of pneumatic components for such apparatus which permits the sieve beds or adsorber columns to be arranged in a modular fashion.
The use of concentrators of the pressure swing adsorber type to produce an enriched product gas is well known. This technology has found its principal application in the field of oxygen concentrators for home health care use. There are numerous large scale industrial applications wherein pressure swing adsorption principles are used to generate supplies of oxygen or nitrogen. Perhaps the most visible use of this technique is in oxygen concentration aboard civilian or military aircraft.
Pressure swing adsorption (PSA) gas concentrators adsorb undesired gases in a compressed air stream. For example, a well known way in which this process is used involves applying compressed air to a first adsorber column which is filled with molecular sieve. As the compressed air flows through the column, the undesired gasses are adsorbed by the molecular sieve, while the desired gas is allowed to pass through the column, where it is extracted as concentrated product gas. When that first column has produced a predetermined amount of gas, the compressed airstream is applied to a second or opposing adsorber column which has previously been regenerated. The second column then becomes the active adsorber concentrating the desired gas while the first column is being regenerated.
Regeneration occurs simply by venting an adsorber column to the atmosphere, which causes the previously adsorbed gasses to escape and diffuse out of the system as vent gas. To further aid regeneration, a small amount of product gas from the opposing adsorber column is used to purge any residual gasses present in the adsorber column being regenerated.
At this point, the first adsorber column is regenerated and again ready to be exposed to the compressed air source and to concentrate gas. This cyclical process repeats to continuously concentrate gas in a regenerative fashion requiring no consumable or expendable materials.
The varying applications of the PSA process, as described above, cause widely varying requirements for the capacity of the PSA apparatus to be used. Heretofore, in order to meet these varying capacity requirements it has generally been necessary to custom design and manufacture the appropriate PSA apparatus, and if capacity requirements changed, an entirely new apparatus had to be assembled. Each requirement has in general resulted in the need for a completely changed assemblage of components including pneumatic fittings, tubes, sealants and the like. It would be desirable to be able to provide a PSA gas concentrator apparatus which is, for example, of modular construction so that the apparatus can be readily modified to meet changing needs.
It is therefore, an object of this invention to provide apparatus for meeting a variety of industrial gas requirements using pressure swing adsorption gas concentrator techniques.
Another object of this invention is to provide a structural arrangement for pressure swing adsorption gas concentration apparatus by which sieve beds can be stacked, as necessary, in a modular fashion to create the capacity needed for a given application.
A further object of this invention is to provide a manifold head structure for adsorber columns used in pressure swing adsorption gas concentration apparatus, which contains all the pneumatic components and provides for all the interconnecting of the ports and passages of the pneumatic logic circuit necessary to carry out the PSA process and which can simply be connected together to form a PSA apparatus of a desired capacity.